Islands of Stability

Opening Questions How could you change a copper atom into a gold atom? What would you need to change? Give specific numbers. Why is this change called a nuclear reaction?

Isotope Notation Atomic Mass Protons + Neutrons Atomic Number Same as the number of protons

Nuclear Chemistry The study of the nucleus of the atom. Protons and Neutrons in the nucleus. + protons and neutral neutrons. Do like charges repel? Force that holds nucleus together is very powerful. “Strong Nuclear Force”

Strong Nuclear Force The strong nuclear force is usually strong enough to keep all of the + protons and neutral neutrons together. When the strong nuclear force isn’t strong enough, the nucleus loses pieces (radioactivity) or breaks apart into 2 or more different atoms (fission).

Purpose of activity Some combinations of neutrons, electrons, and protons are not stable enough to be called elements. You will learn how to predict the numbers of neutrons, electrons, and protons of the isotopes commonly found in nature.

Post-Activity Questions If an atom has the same number of neutrons as it does protons, are you likely to find it in nature? Explain. In general, what is true about the relationship between the number of neutrons and protons in an element? What is the ratio of neutrons to protons for small atoms? For large atoms?

Notes: Radiation vs Radioactivity What is the difference between radiation and radioactivity? Radiation: general term for any type of energy that radiates outward in all directions (Ex: light or heat). Radioactivity: occurs with the breakdown (decay) of certain unstable atomic nuclei

Notes: Stable Nucleus vs Unstable Nucleus STABLE nucleus is an atom with the “correct number of protons and neutrons” as shown on the Per. Table. Will lie in the “Band of Stability” on chart. An UNSTABLE nucleus is an atom that will undergo spontaneous decay because the atom does not have the correct proton/neutron ratio. In other words, atom has more or less neutrons that it should. An atom with an unstable nucleus can also be called a radioisotope.

Exit Questions Use your graph to determine how many neutrons you would need to make a stable element with 75 protons. Imagine an atom with a nucleus of 31 protons and 31 neutrons. Does this represent an element? Why or why not?